It is proposed to establish the influence of race, sex and age and State of residence on the mortality from malignant melanomas and other skin tumors in the population of the U. S. and the trends with time through 1950- 1967. Unpublished official data will be used. The relationships cannot be established with data that are currently available. The findings will be related to those of the incidence of malignant melanoma and other skin cancer, derived from the National Cancer Surveys and from American population based cancer registries, and to foreign incidence and mortality data. They will also form a necessary background to large scale clinical and pathological studies of malignant melanoma now under review. Total death rates from skin tumors are rising in young adults, due to a real increase in the incidence of melanoma. This change is probably due to greater exposure of poorly pigmented people to sunlight. The long term objective is to develop means of identifying those at risk, so that they can receive specific advice, while the majority of the population can be rationally reassured. The establishment of the behavior of groups is an essential preliminary to the development of sufficient knowledge for application to individuals. It has been suggested that the operation of numbers of large supersonic transport aircraft will reduce the ozone shield and allow an increase in the intensity of terrestial ultraviolet radiation. Most skin tumors are produced by sunlight, and it is important to have base line studies and estimates of trends against which any effects on atmospheric shielding by these aircraft can be judged. The relationships between exposure and melanoma and other tumors are complicated, and current theoretical ideas do not provide satisfactory explanations of experience. The analysis of this large body of data will enable theoretical schemes to be modified.